Genetic correlations between pulpwood and solid-wood selection and objective traits in Eucalyptus globulus

Abstract

• If selective breeding is to be successful, significant genetic variation must be present in the traits targeted for improvement (i.e. “objective traits”).• This study aimed to quantify genetic variation in Eucalyptus globulus pulpwood and sawn-timber objective traits (rotation-age whole-tree volume, survival, whole-tree basic density, sawn-board Janka hardness and sawn-board internal checking) and estimate additive genetic correlations between these and inexpensively-assessed “selection traits”.• Significant genetic variation was identified in all objective traits at the subrace and/or family within subrace level.• Selection-age diameter at breast height (1.3 m, DBH) was strongly genetically correlated with rotation-age volume (0.78) and survival (0.82). Subrace and additive genetic correlations of selection-age Pilodyn penetration with rotation-age 12- × -12-mm-sample basic density (–0.70 and –0.75 respectively) and whole-tree basic density (–0.83 and –0.91 respectively) were also strong.• No significant subrace or additive genetic correlation between wood-sample gross shrinkage and sawn-board internal checking was detected. However, subrace and additive genetic correlations of sawn-board Janka hardness with Pilodyn penetration (–0.75 and –0.58 respectively) and sample gross shrinkage (–0.77 and –0.73 respectively) were significantly different from zero.• These findings suggest that genetic improvement of the examined objective traits is possible through selective breeding, although none of the assessed selection traits were strongly correlated with internal checking.